CN1102220A - Method for applying diamond film to hard alloy tool knife-edge - Google Patents

Abstract

The present invention provides a preparation method for growing diamond film only on the tip and cutting edge of tool and its nearby zone to obtain the hard alloy tool with high-performance diamond film coating, i.e. after the substrate surface of hard alloy tool is treated by using focused laser beam, a polyethylene (or other polymer and plastics) solution is used to make masking treatment, and after the above-mentioned material is activated by using diamond powder, the mask can be removed, so that any existent chemical vapour phase deposition process of diamond film can be used to achieve the goal of growing diamond film only on the tip and cutting edge of hard alloy tool and its nearby zone.

Description

Method for applying diamond film to hard alloy tool knife-edge

The invention belongs to the technology that on Wimet, prepares the ultrahard diamond coated tool with chemical gaseous phase depositing process, adopt technology of the present invention can only allow diamond film partly grow at the wedge angle and the cutting edge of carbamide tool, improve the bonding force between chemical vapor deposition diamond film and the substrate greatly, prepare high performance diamond film coating layer carbamide tool.

Diamond coating for hard alloy tool has begun on market (Japan) and has occurred, and has demonstrated very remarkable cutting ability (when the cutting silumin, it is tens of to hundreds of times to improve life tools, and can improve suface processing quality greatly).But, because the existence of the cobalt phase in the Wimet makes the diamond thin vapor phase growth be difficult to carry out.Cobalt promotes the generation of graphite, thereby the overslaugh growth of diamond also finally causes diamond film and very fragile the combining of cemented carbide substrate.At this problem, from about 86 years, existing up to a hundred patents are delivered in the Japan and the U.S..These patent attempts are passed through: (1) reduces the content of cobalt in the Wimet as far as possible, adds special additive, or adopts non-cemented carbide substrate; (2) adopt acid liquor etching, electrolytic etching, plasma body etch and at H ₂O-O ₂The method of high temperature carbonization treatment is removed the cobalt of carbide surface layer in the atmosphere, (3) apply metal or compound barrier layer, (4) adopt various surface modifying treatments to make the substrate surface roughening, (5) adopt special deposition technique to obtain the complicated multilayer complex films of preparation, eliminate the harmful effect of cobalt, strengthen the bonding force between diamond thin and cemented carbide substrate, in the hope of obtaining practical diamond coating for hard alloy tool.

Remove outside the harmful effect of cobalt in the Wimet, the internal stress that chemistry for gas phase depositing diamond film itself exists also is an important factor that influences bonding force.United States Patent (USP) (US PATENT 4919974,4992082,4998421 etc.) has adopted a kind of very complicated method attempt to solve the problem (see figure 1) of internal stress.The essence of this method is to substitute the successive diamond film with the dispersive diamond particles.At first on the carbamide tool substrate, deposit one deck blocking layer to prevent the influence of cobalt, then at deposition one deck dispersive diamond particles (discontinuous diamond film), then deposit one deck key coat (BONDING LAYER, this layer all has good the combination with diamond particles and blocking layer) again.Carry out the deposition of diamond particles and key coat subsequently more repeatedly, finally obtain a kind of very complicated multilayer film system.Obviously, this method technology is too complicated, and cost is too high, and unsatisfactory by the diamond coatings tool performance of this method preparation.Japanese Patent JP03-215669/1991 has proposed a kind of more efficiently terms of settlement, adopt the tantalum (or thin tantalum piece) of chemical vapour deposition to make mask, only allow diamond the wedge angle of carbamide tool or cutting edge and near 0.5 millimeter region growing, thereby eliminate the influence of internal stress effectively, improve the use properties of diamond film coating instrument widely.

The object of the present invention is to provide a kind of masking method different with aforesaid method, realize diamond film only carbamide tool wedge angle and cutting edge and near the deposition of regional area.

The present invention is based on following principle: promptly when activating the substrate of (SEEDING) with diamond powder with high energy laser beam irradiation process, activation particle (being likely the diamond powder fragment that embeds substrate surface) will be burnt by laser beam, so the regional adamantine forming core of every process laser beam treatment will be suppressed.This principle (is seen DD﹠ST for the scholar of physics Institute of USSR (Union of Soviet Socialist Republics) academy of sciences, 3(2) 1992: 4) work on silicon substrate confirms, but do not see as yet that up to now any employing laser beam is implemented in the report of carbamide tool wedge angle and cutting edge and near growing diamond film thereof.

The present invention includes following content (see figure 2): 1) adopt the carbamide tool substrate of high energy laser beam irradiation through overactivation (SEEDING), 2) with polyethylene solution be coated with (or organic solution of other polymkeric substance or plastics) multiple except that instrument wedge angle and cutting edge and neighbouring All Ranges, promptly form polyethylene mask (or other polymkeric substance or plastic film) after the drying, 3) the carbamide tool substrate of mask process is carried out activation treatment in the ultrasonic bath of the water of suspension fine diamond powder or organic solvent, 4) remove polyethylene mask, 5 with acetone or other organic solvent) adopt existing any diamond film chemical gaseous phase depositing process removing growing diamond film on the instrument substrate of polyethylene mask.Adopt method of the present invention, diamond film can only not add the part of mask, i.e. tool edge and wedge angle and near growth thereof.

Can use excimer laser, or carbon dioxide laser, or YAG laser shines to cemented carbide substrate, but ideal with excimer laser.When adopting excimer laser, best energy density scope is: 0.5-4.0J/cm ², 100 nanoseconds of pulsewidth, 10 hertz of frequencies.The purpose of laser treatment not only is to burn the activation particle of substrate surface, the more important thing is by this processing makes the cobalt on Wimet top layer be removed by the evaporation of selectivity, also make surface modification reach suitable roughening simultaneously, improve the bonding force (inventor's patent applied for) of diamond film and carbamide tool substrate widely.Mask also can adopt other polymkeric substance or plastics except that adopting polyethylene.Activation treatment after the mask process is most important, can adopt the suspension of bortz powder in water or organic solvent (as methyl alcohol, the organic solution of employing should not dissolved mask) of 0.5-40 μ m, supersound process 10-120 minute.Final chemical vapour deposition can be adopted any existing diamond film deposition technology, comprises heated filament CVD, microwave plasma CVD, DC arc plasma CVD(DC PLASMA JET), flame deposited etc.Under the situation that adopts microwave plasma CVD, typical processing condition are: H ₂: 50-500sccm, CH ₄: 0.2-10sccm, underlayer temperature: 600-1000 ℃, microwave power: 200-2000W, depositing time: 5-15 hour.

The invention has the advantages that: 1) masking method is simple, with low cost, 2) laser treatment before the mask is except that the effect of the activation particle of burning-off substrate surface, can also remove the cobalt of upper layer by preferential evaporation, simultaneously because the transient melting and the rapid solidification on surface can also make the carbide substrate surface roughening, strengthen the bonding force between gas-phase grown diamond film and the cemented carbide substrate greatly, improve the use properties of diamond coating for hard alloy tool and (see the relevant patent that the inventor applies for: new process of chemical gas-phase deposition of diamond coating for hard alloy tool).

The present invention is further illustrated below in conjunction with accompanying drawing.

Fig. 1 is the method synoptic diagram that United States Patent (USP) (US PATENT 4919974,4992082,4998421 etc.) attempt solves the problem of internal stress.The essence of this method is to substitute the successive diamond film with the dispersive diamond particles.59,61 is the blocking layer among the figure, and 62,65,67,70 is diamond particles, and 64,66,68 is key coat.This method technology is very complicated, with high costs, and the carbamide tool use properties of preparation according to said method is unsatisfactory.

Fig. 2 is a processing method synoptic diagram of the present invention.[1] high energy laser beam irradiation among the figure, [2] mask process, [3] remove mask, [4] activation treatment (SEEDING), [5] diamond chemical vapour deposition.

Embodiment 1 YG6(WC-6wt%Co) carbide-tipped milling cutter employing energy density is 2.0J/cm ²Excimer laser beam handle (cutter front, and side 0.5mm scope), make mask with polyethylene then, only expose the wedge angle and the cutting edge part (see figure 2) of cutter.With the cutter of mask process supersound process 30 minutes in the bortz powder methanol solution of suspension 20-40 μ m granularity.With acetone solution polyethylene mask, after with the ultrasonic cleaning of clean methanol solution, insert and carry out the diamond film vapour deposition in the microwave plasma CVD device.Deposition process conditions is: gas composition H ₂100sccm, CH ₄1sccm, pressure 20 torrs, 400 watts of microwave powers, 850 ℃ of underlayer temperatures, depositing time 5-15 hour can 0.5 millimeter acquisition thickness be the diamond coatings of 4-10 micron near cutter wedge angle and cutting edge.

Embodiment 2 carries out the same laser treatment, after mask process and the activation treatment, adopts hot filament CVD to carry out the diamond film chemical vapour deposition.Processing condition are: gas composition H ₂100sccm, CH ₄0.5sccm, pressure 20 torrs, 2000 ℃ of filament temperatures, 850 ℃ of underlayer temperatures, depositing time 6-15 hour.Can near cutter wedge angle and cutting edge, 0.5 millimeter acquisition thickness be the diamond coatings of 4-10 micron.

Claims (2)

1, a kind of technology that on inserted tool, prepares the diamond film coating instrument with low-pressure chemical vapor deposition method, it is characterized in that adopting special masking method, only at wedge angle and the cutting edge and the near zone depositing diamond film thereof of instrument, promptly adopt excimer laser, or carbon dioxide laser, or YAG laser shines cemented carbide substrate, and when adopting excimer laser, best energy density scope is: 0.5-4.0J/cm ²100 nanoseconds of pulsewidth, 10 hertz of frequencies, adopt then polyethylene or other polymkeric substance or plastic solution coated except that instrument wedge angle and cutting edge and neighbouring All Ranges, promptly become desired mask after the drying,, should in the ultrasonic bath of the water of suspension fine diamond powder or organic solvent, carry out activation treatment subsequently through the cemented carbide substrate of mask process, for well, the time is 10-120 minute to the bortz powder granularity with 20-40 μ m.

2, low-pressure chemical vapor deposition method according to claim 1 prepares the technology of diamond film coating instrument, it is characterized in that cemented carbide substrate through above-mentioned processing, after removing the polyethylene mask, can adopt present all diamond film chemical gaseous phase depositing process to finish the coated of diamond film with acetone or other organic solution.Comprise microwave plasma CVD, hot filament CVD, plasma spraying (PLASMA JET) and other existing technology, thus only can realize the inserted tool wedge angle and near the part growing diamond film, prepare high performance diamond film coating instrument.